A light emitting diode (LED) is a blue or ultraviolet (UV) LED particularly having an emission wavelength of approximately 250 to 550 nm, which is a high-brightness product using a GaN-based compound semiconductor such as GaN, GaAlN, InGaN or InAlGaN. In addition, it is being possible to form a high-quality full-color image by a method of combining red and green LEDs with a blue LED. For example, a technique of manufacturing a white LED in combination of a blue or UV LED with a phosphor has been known. Such an LED is being widely used for a back light for a liquid crystal display (LCD) or general lights.
As an LED encapsulant, an epoxy resin having a high adhesive property and excellent mechanical durability is being widely used. However, the epoxy resin has a lower light transmittance of a blue light or UV ray region, and low light resistance. Accordingly, for example, in the patent documents 1 to 3, techniques for solving the above-described problems. However, encapsulants disclosed in the above references do not have sufficient thermal resistance and light resistance.
As a material having excellent light and thermal resistances with respect to a low wavelength region, a silicon resin has been known. However, the silicon resin has stickiness on a cured surface. In addition, to effectively apply the silicon resin as an encapsulant for an LED, characteristics such as high refractivity, a crack resistance, a surface hardness, an adhesive strength and a thermal and shock resistance are necessarily ensured.